Application of Wireless Monitoring Technology in Subway Video Surveillance System

Wireless video surveillance technology is used in many security areas. The subway safety guard system is an important equipment to ensure the smooth running of the subway and the safety of transportation. The use of wireless video surveillance technology in the metro video surveillance system.

Demand analysis For the metro, the first thing to monitor is the need for safe operation and explosion protection. Due to the large passenger flow and complicated personnel, the subway system is a underground space with closed, opaque and unfavorable ventilation. Once an accident such as fire or explosion occurs, the impact will be very great. Therefore, it is necessary to intercept suspected explosives in advance, including Some liquids, solid explosives, and toxic gases, etc., are fully protected. In order to prevent passengers from carrying flammable and explosive materials and other suspicious items that may cause major public safety accidents, the station has also strengthened security measures. However, the existing security inspection equipment only performs security checks on people and objects, and all kinds of insecurity The hidden danger still exists, so the monitoring of the situation inside the subway car has always been a function that everyone expects, but due to the limitations of the wireless transmission bandwidth and movement speed has not been well achieved, with the issuance of China 3G licenses and 3G networks. It has become feasible to conduct real-time video surveillance in high-speed subway cars. ZTE Corporation, as the leading domestic 3G market leader, has launched a “Wireless Video” video monitoring system for subway wireless solutions in line with market needs. It has adopted networked and intelligent video surveillance technology to achieve full coverage of video surveillance in subways. Application, share some experiences with everyone here.

Wireless fixed-line converged video surveillance solution design system architecture "Network video" video surveillance system adopts all-IP technology to provide an integrated end-to-end solution combining mobile network and fixed network, which can provide WiFi/2.5G/2.75G/3G Various wireless network monitoring front-ends such as WiMAX, and a full range of multi-functional cable monitoring front-ends, system management platforms and portals, media distribution and storage platforms, and multiple monitoring clients (including mobile client/PC client/WEB Client/hardware decoder, etc. A series of hardware and software devices.

The system is based on the excellent fixed network and mobile all-network design concept. It adopts software modular design and advanced intelligent transcoding gateway design scheme according to the requirements of carrier-class reliability. It can provide excellent mobile and fixed-line converged video surveillance. Comprehensive application. For the metro system monitoring, its network architecture is shown in Figure 1.

Front-end design In the subway car, according to the situation of the wireless network, configure the dedicated vehicle-mounted 3G wireless video server + dome camera with the corresponding interface. The wireless video server itself can be configured with a hard disk to achieve local storage of high-definition, real-time video (D1 format). According to the 3G network transmission speed, a CIF real-time or D1 non-real-time (down frame) video uploading platform is set up for use by the monitoring center and related management personnel. In the event of an accident, local video recordings stored in the D1 format can be directly retrieved.

For each station station and the monitoring points set at the entrances and exits of the building (upholstery), etc., you can directly use network cameras, such as network high-speed ball, network guns, etc., to reduce the difficulty of construction, and you can also use simulation. Camera + Video Encoder Way Construction.

Access network design For vehicle monitoring points, 3G wireless networks are recommended, such as the latest 3G or 3.5G wireless network technologies such as Telecom's CDMA EV-DO or China Mobile's TD-SCDMA HSPA+, to ensure sufficient upstream bandwidth. Can upgrade to LTE network. For fixed monitoring sites in the station, it is recommended to use wired access to the network to ensure the stability and reliability of access.

Monitoring Center Design Metro monitoring system monitoring center generally consists of three types, from the management can be divided into three levels, the first type of station monitoring center, a large number, each station has a local monitoring center to achieve the site monitoring image The browsing has the highest authority over the control of this site's camera; the second type of monitoring center is the line subway dispatching and management center. There is generally one line per line and it is necessary to know the general conditions of each station and the details of the train operation at any time. All videos of the station can be selectively viewed, but the control authority of the camera is one level lower than that of the station. The third category is the vehicle maintenance center. Generally, one line has 1-2 maintenance centers, and the target of monitoring is mainly It is a variety of hardware and equipment for stations and subway trains. It has control rights for certain cameras and has the lowest control authority. The network structure of the line monitoring management center and station monitoring center is shown in Figure 2.

Mass storage design In order to save a large amount of video recording data, a central mass storage device needs to be established. According to the characteristics of video surveillance video recording, it is recommended to use IP-SAN storage technology. Because IP-SAN has the following advantages over other storage methods:

High cost performance

·Strong ability to expand;

·Centralized management;

The Ethernet network technology is quite mature, reducing the complexity of configuration, maintenance and management;

· Network-based storage systems, data migration and remote mirroring are easy, as long as the network bandwidth support, there is basically no distance limit, can better support remote disaster recovery;

Easy integration with existing monitoring Ethernet networks;

The network is not limited and easy to deploy.

IP-SAN combines the speed and cost of SCSI with the commonality and universality of IP networks and Ethernet, making IP-SAN storage solutions a cost-effective, scalable, and well-known solution.

In the project, it is recommended to use dual-controller magnetic arrays. One main cabinet can be expanded to connect three sub-racks and provide 51 hard disk slots. Multiple IP-SAN arrays can be configured in the project to achieve large-capacity storage.

The system platform design and monitoring system platform is divided into two parts: the service management platform and the media service platform. It completes the equipment and user overhead management, AAA management, business management, equipment configuration management, platform networking management, operation and maintenance, and remote upgrade of the entire system. Management functions, as well as video storage, sub-forwarding capabilities, provide full network support for business use.

In order to ensure the security of the system structure, the management center CMS+Distributed Video Surveillance (VSS) media node is used to build the system. The CMS equipment is placed in the Metro Monitoring Center and can be set as a VSS media node in each station. The cameras at the two stations are centralized to build a VSS media node to reduce the bandwidth occupied by video in the entire transmission network of the subway and improve the security of the system.

The multiplication of intelligent application design monitoring points brings more video information. Massive transmission of video information means higher bandwidth resources, more storage space, and more people analyzing, judging, and processing video information.

At present, the traditional monitoring system is to monitor the surveillance screen by the staff on duty 24 hours a day, based on the person's judgment on the content of the video information, analyze and deal with the abnormal behavior, and ensure the basic safety of the community through the close combination of air defense and technical defense. However, it turns out that after 20 minutes of staring at the monitor screen, the attention of the human eye will be seriously reduced, and in the face of a large number of surveillance screens, the possibility of finding an abnormal behavior is relatively small. Based on the physiological characteristics of human beings, it was originally expected to increase the security level by increasing the number of electronic eyes. Now, because of the rapid increase in video information, it is impossible to achieve the desired purpose. For the security sector, video surveillance images are an important source of clues in the detection of major cases. For video clues that may have clues, they are often viewed for dozens of days and the traditional one-frame playback is contrasted. The method greatly increases the difficulty of the forensic investigation and the period of investigation.

The intelligent video analysis system can better solve the above problems. The system adopts international advanced image processing, pattern recognition and computer vision technologies to alert and alarm the abnormal behaviors in the video surveillance scene, thereby constructing a fully automatic, All-weather, real-time monitoring of intelligent systems. The intelligent video analysis system converts the traditional person-attended passive monitoring mode into an active event management and convenient post-search analysis mode. Through real-time video, it automatically discovers suspicious conditions and intelligently analyzes the alarm devices in the first time. Management system. At the same time, the intelligent analysis system server can flexibly access all relevant front-end devices in a specified area of ​​the IP broadband network, and does not require special upgrades and complicated settings, and the access capability can fully meet the current needs.

Intelligent video analysis technology is often deployed in two ways. One is to use an embedded architecture, and to perform local operations and analysis by embedding intelligent video analysis software in video equipment such as video servers and network cameras with DSP processing chips. The screen used is the CIF format. The biggest advantage of this method is that it uses distributed processing to reduce the number of analysis servers. Its big drawback is that the deployment is not flexible enough and it is not convenient to adjust the device after it is installed. The second method is to adopt the background processing method. Through the integration with the monitoring platform, the digital code stream is obtained from the network video monitoring platform. After the decoding, direct analysis is performed. All the analysis is centralized in the monitoring center room. Adjusting and modifying the front-end camera that needs to be analyzed has nothing to do with the location of the camera. This is its biggest advantage. It can fully save and utilize resources, and it can be expanded according to need, without needing to be in place once. The biggest drawback is the increase in the number of analytical processing servers and may lead to increased network traffic. In this system, a streaming media server is used for media distribution and relay. The background processing method does not add extra network traffic. Therefore, it is recommended to use the background processing method to build an intelligent video analysis system application.

In addition, the system can also provide intelligent analysis capabilities include items left alarm, regional intrusion alarm, face recognition deployment control, abnormal behavior analysis and alarm, traffic statistics and analysis and alarm functions.

System Advantages Introduction The system's subway solution provides flexible mobile access methods and enables seamless coverage of video surveillance. The system also has the following features.

IPTV large-capacity system basic technology, distributed network architecture, modular design · Adopt IPTV large-capacity sub-forwarding technology architecture to achieve a user capacity of more than one million system users;

Distributed network architecture, using system management center + node mode;

· Modular design, the entire system includes the central management system CMS, media distribution network VDN, media scheduling unit, streaming media server SS, dedicated interface and other parts, all can be deployed independently;

Adopt dual-system hot backup or load balancing to achieve functional module-level security.

Decentralized domain and fine-grained rights management. Flexible support for the industry's customer-level management capabilities, which enables the group's internal customer self-management, to achieve the overall operation of the monitoring business, and can be divided for different users storage and forwarding resources;

· Video browsing permissions: including real-time video playback;

· Configuration management authority: includes the configuration of front-end device video parameters, alarm switch settings, alarm parameters, and alarm linkage configuration;

· Video plan configuration authority: including setting up monitoring point regular video plan;

· Video browsing permission: including video file query, video and video playback;

· Cloud mirror control authority: including cloud mirror control operation, a total of 9 levels;

Alarm management authority: including alarm information receiving and alarm information processing;

Language communication rights: including language intercom, voice broadcast, etc.

· User management authority: including management operator account configuration;

· Device management authority: including management of PU devices and channels;

· TV wall management rights: including the configuration and use of video walls;

Electronic map permission: including the configuration and use of electronic maps.

Unified network management and maintenance, unified management of the whole network equipment, and SNMP+TR069 protocol are used in the system to build a unified network management system.

· Master devices such as platform servers and core switches adopt the SNMP protocol for network management;

• Large and constantly changing video coding equipment PUs and client CUs use the TR069 protocol for network management. The operation is simple and can be integrated into the ITMS unified network management platform.

Unified User Account Authentication: The user's mobile phone number can be used as a unified account for the user to use the system.

High Security Clients provide USB Key security authentication, MAC address and IP address or address segment binding, simultaneous login account limit, user password and account expiration settings, and regular change of password prompts to ensure client use Security;

· The platform server adopts the Linux operating system, configures hardware firewalls, kills virus software, and adopts reinforcement measures such as port blocking and access restrictions to ensure the security of the platform.

Adopting streaming media packaging technology to ensure media transmission and storage security through MD5 signaling encryption, media fragment storage, and dedicated transcoding tools;

Supports the mutual preparation of POP units within service nodes and the mutual preparation of service nodes, and fully guarantees the high reliability of the system from the application layer.

Fixed network and mobile surveillance convergence support, intelligent transcoding and system support fixed network and mobile monitoring services at the same time, providing MSP, PSS, VAU, wireless PU, M_CU and other full range of mobile monitoring module components, without other manufacturers to participate in the building A complete set of converged video surveillance business solutions;

The system can adapt to various network environments, including: wired networks (xDSL, LAN, xPON, E1), etc.; wireless networks (CDMA1X, EV-DO, WCDMA, EDGE, TD-SCDMA, HSD/UPA, WiMAX, WiFi), etc. ;

The system can be integrated into the fixed-line front-end, mobile front-end, fixed-line/mobile dual-mode front-end, and supports multi-stream PU devices;

The system supports fixed network, mobile phone monitoring client access services;

· For 3G mobile network applications, the system can provide intelligent transcoding capabilities, and automatically select the optimal transcoding scheme through the intelligent transcoding mechanism to output the media stream suitable for mobile phone playback.

Cloud Mirror Locking Function • Support users to lock the PTZ. Other users cannot operate the PTZ while the user is locking the PTZ. Only the current user can control and unlock the PTZ.

· After the cloud mirror is locked, the client gives a corresponding prompt when other users operate, such as "The cloud mirror has been locked by user XXXX, and operation is not allowed";

·Enterprise initialization administrator can force unlock;

· The user is allowed to perform a lock operation on the channel only if the account has the permission to lock the mirror and the cloud mirror control permission of the corresponding channel has been allocated.

The MOC client, WMPortal, and MOCPlayer all provide this function.

Provide professional network quality analysis tools and system maintenance management portal. It supports the display of external IP addresses and intranet IP addresses of PUs at the same time, effectively assisting operators in business management and maintenance;

Integrated professional network quality detection and analysis functions in the client. When the client plays a video display, green screen, or card, it can display the abnormal network status on the client side, helping the user to locate and resolve the fault.

Supports the display of network status in the status bar of the MOC client, including information such as total code rate, packet loss rate, and jitter;

Supports diagnosis of network conditions. Statistics such as packet loss, packet loss rate, bit rate, number of out-of-order packets, frame size, network jitter, etc. can be calculated and the network status can be graphically displayed.